EXPRESSION AND SECRETION OF ASPERGILLUS-NIGER GLUCOAMYLASE IN SACCHAROMYCES-CEREVISIAE

Aspergillus niger glucoamylase GA I cDNA was inserted in between the y east PGK promoter and terminator on plasmid pMA91. The resultant plasm id pMAG69 was introduced into Saccharomyces cerevisiae GRF18 by protop last transformation. The A. niger GA I cDNA was expressed efficiently under the control of PGK promoter and 99% of the gene products were se creted into the culture medium using its own signal sequence. The reco mbinant yeast can digest 87% of starch in 2 d in the medium containing 10% starch. The recombinant plasmid pMAG69 on exist stably in S. cere visiae.